Last Updated on July 22, 2024
Are French Doors Safe? | Biggest French Door Security Flaw | The #1 French Door Security Tip | Prevent Door Glass from Breaking | Install High-Security Locks | Install Door Reinforcement | FAQ
French doors are one of the weakest security points in your home due to two individual doors meeting in the middle. When they are not properly locked, or the locks provided during the installation have not been modified, these doors can be made to easily swing open even when the deadbolt and door lever have been locked.
To secure French doors: 1) Install a screw that prevents the unlocking of the passive door, 2) Install security film to protect the glass from being broken out, 3)Install new locks that join both sides of the door together so that they cannot be separated by swinging both sides open at the same time.
Why French Doors Need Better Security
French Door Design
French doors, or double doors, are composed of two doors that meet in the middle. One door is referred to as the passive door. This is the door that is seldom used. The other door is referred to as the active door. This is the side that is normally opened and closed.
French Doors also have specific security concerns that make them more vulnerable to burglary than a standard door. Once you’ve addressed that specific double-door weaknesses, reinforcing a French door is just like reinforcing any other door.
We have written an article on How to Reinforce an Entry Door in 6 Easy Steps. Everything in that article applies here as well.
The specific security weakness of a French door comes is due to the two doors meeting in the middle. The passive side of the door is seldom used so it is secured into the top and bottom of the door frame using a slide bolt or flush bolt.
The active door is then locked to the passive side of the door via a deadbolt and door knob/lever. This method of securing double doors relies heavily on the passive side of the door being secured to the door frame at all times.
Should the passive side of the door not be secured to the frame, the two doors can be pushed open without any resistance, even though the deadbolt of the active side is locked into the passive side it will just slide out as the two doors open simultaneously. The photo below illustrates this point. It is viewed as if looking down on the door from the top.
French Door Security Flaw
As long as the passive door remains secure to the door’s frame, then there should be no problem.
However, the passive side of the door can easily be unlocked so that it is no longer secured to the frame.
If you position any thin, rigid device into the seam between two doors, you can use it to catch the flush bolt, and then slide it to the unlocked position. Once the slide bolt is unlocked, the two doors will freely swing open despite the active side of the door being locked.
#1 Security Fix for Double Doors
This technique is the simplest, cheapest and easiest. If you do nothing else, do this. It won’t address any other security weakness of the double door (such as the glass), but it will prevent someone from getting into your double doors undetected as we’ve just discussed. All it takes to prevent this bypass is a single screw.
The passive side of the door is very seldom used. Most homeowners only unlock it and use it when they are trying to get something very large into or out of the house.
Keeping that in mind, we recommend screwing screws into each flush bolt so that they cannot be slid open until the screws are removed.
This simple, cheap, DIY, double-door security improvement will prevent the above-mentioned break-in technique 100%.
To do this, slide the flush bolt into the door’s frame, securing the door. Then screw a small screw into the bottom of the flush bolt so that the bolt can not be slid open until the screw is removed.
If at some point, when you need to use the passive door, simply remove the screws. Then reinstall them when you are ready to lock back up.
This technique, combined with the How to Reinforce an Entry Door in 6 Easy Steps, will make your double doors as secure as any door or window in the house.
Install Glass Door Window Film
Glass security window film has come a long way. A DIY installation of glass security film is now easily performed by most homeowners and the security film will greatly enhance the security of a French door by preventing the glass from being easily broken to unlock the door.
Security window film is a film that is attached to the glass. This film is several millimeters thick but clear so that the beauty of the door is not diminished.
When applied to the glass, it acts to hold the glass together so that when the glass is hit, it will not break out. The glass does actually break, but the film holds it together in place.
For the best installation of the security window film, remove the panel, install the film, and replace the panel into the window. When this is not possible, we use a thin bead of clear silicon around the edge of the window.
Security film is available at Home Depot.
Install High-Security Deadbolts
When I have customers with large valuables in the home with double doors, we often increase the security of the French doors by:
- Installing a double-sided, high-security deadbolt into the active side of the French door.
- Adding one-side half deadbolts to the top and bottom of each door.
High-Security Mul-t-Lock Deadbolt Holds the Doors Together
When it comes to high security Mul-t-lock is our favorite brand. We discuss it in our online article, Best Lock Brands.
The Mul-t-lock has a feature here that is ideal for double doors. In a Mul-t-lock lock, there is a ball bearing in the bolt that will secure and lock into the strike of the other door. This makes the two doors very difficult to pull apart! So even if the slide bolts have been removed, the two doors will open partially but hold together and cannot be swung completely open.
If you are investing in a Mul-t-Lock (check out the prices on Amazon) for a double French door, you do not want to get one with a thumb turn on the inside of the home. Buy a double-cylinder deadbolt that takes a key on both sides. This way, should the glass be broken out, the deadbolt cannot be opened using the thumb turn.
Upgrade the Door Frame Bolts
Another big boost in French door security comes from eliminating the flush bolt. One-sided deadbolts are the best deadbolts for home security. This deadbolt has a thumb turn on the inside of the home, but no indication (no keyhole) on the outside of the home. That is, there is no way to tell from the outside of the home that a deadbolt is installed.
We install these at the top and bottom of both double doors. When combined with window security film and an interlocking Mul-t-lock deadbolt, your double door is virtually impenetrable, and when you want to use both doors of the French door, you won’t need to unscrew screws; you just unlock the deadbolt using the thumb turn.
Home Depot sells our favorite half-deadbolt (the Schlage B80 on Amazon) for less than $25 at the time of this article.
To install them though, you will need to drill holes halfway through both of your doors for the deadbolts. This is beyond the skill of most DIYers. So we recommend calling a locksmith in your local area.
How to Reinforce a Double-Door
In the beginning of this article we touched on the How to Reinforce an Entry Door in 6 Easy Steps article. Again, all the same security tips for any entry door also apply to your French door security.
There is one notable difference, that of the door reinforcement kit.
If you want to reinforce a double entry door, you will need a single door reinforcement kit and add two extra hinge protectors and a floor-mounted door barricade, such as the Night Lock on Amazon.
The door reinforcement kit will provide kick and force resistance by wrapping all critical components with metal and installing 3″ screws in place of the 1/2 screws likely installed during construction.
The door barricade adds another layer of protection by securing both of the doors simultaneously from being forced open. Floor door barricades are easy to remove when you want to use the door.
Getting the Best French Door Security – Summary
Securing your double French doors from the easiest bypass technique can be achieved for practically nothing, by adding just one screw, and is the best security improvement you can make to your double doors.
But if you have high valuables and you want to secure the French door as much as possible, numerous additional things can be done to beef up the integrity of the door to its highest security level, including installing a lock that stops the doors from being separated.
Which you choose depends on your desired level of security and budget.
FAQ
Are French Doors Safe?
French doors have a major security flaw that needs to be addressed, but once addressed they can be made as secure as the other doors in your home.
Is it Expensive to Secure a French Door?
Our #1 French door security tip costs less than $1 to fix. From there, as you add security, cost can go up depending on the level of security.
Won't People Just Break the Glass?
Possibly, and there are two ways to prevent this. You can stop the glass from being broken using security window film. Or, you can install a double deadbolt so if the glass is broken, the door still cannot be unlocked.
Disclosure: As an Amazon / Google / eBay / Home Depot Associate I may earn from qualifying purchases.
More of Our Favorite Security Products
See our Amazon Store for Videos and Links to All of Our Favorite Security Products.
Door Armor: Reinforce your doors. This video on YouTube shows the installation of Door Armor, and you can buy this or similar products from Amazon at a great price.
Video Doorbells: This video doorbell offers great images and video and has NO monthly video storage fees. Watch our SkyBell Video Doorbell Review on YouTube and buy it on Amazon.
Smart Locks: Access Your Locks via Smart Phone. You’ll find some of our favorite smart locks that allow you to control home access and monitor entry in our Amazon Smart Lock Shop. Watch our Smart Lock Comparison Video on YouTube for reviews of the most popular Smart Locks.
High-Security Safes: When you want a safe that is designed to protect the valuables you put inside, you want a high-security safe found on ACME Locksmith’s Safes for Sale website.
Sliding Glass Door Lock: The best Arcadia door lock that stops your sliding glass door from being lifted out of its tracks and prevents little ones from opening the door and leaving the home. Check out the video on YouTube and Buy it on our website.
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